Many products, including but not limited to food products, have a limited shelf-life, and an important aspect of the management of inventory that includes such products involves some form of monitoring of the expiration dates so that products can be sold before the expiration date or removed from inventory if the expiration date has passed. Typically, such products are marked with an expiration date printed or stamped on the product package in a form, such as text, that enables a potential purchaser to read the date. Basic information about these products is associated with the packaging in the form of UPC bar codes or, increasingly, RFID tags, that can be scanned for various purposes including basic inventory management and control. The UPC or other identifying code for a particular product is unique to that product. However, because the expiration date for distinct items of a particular product type depend upon the date of production of each unit, expiration dates are constantly changing and are not unique. Further, because expiration dates must be directly readable by potential purchasers, it is not feasible for the manufacturer or producer to encode the expiration date on the package in machine readable form.
In, e.g., a grocery store or supermarket, product codes are scanned when the products are brought into the store or placed on the shelves for sale. The information is provided to a computer system and the products are added to inventory. When a product is sold the product code is scanned at the point of sale the sold product unit is deduced from inventory. These systems are very effective on a gross or basic level, but they neither capture nor track information related to expiration dates because that information is not and cannot feasiblely be provided in machine readable form.
Expiration dates must, within the scope of the prior art in this field, be monitored by direct human involvement. In a typical procedure, a person patrols the product shelves, identifies products with expiration dates, and reads the expiration date on each product unit to determine which product units are approaching or have passed their expiration dates. Product units that have passed their expiration dates are typically pulled from the shelves. Procedures for management of product units that are approaching their expiration dates vary, and may include moving the items to a location for quick sale, rearranging product units on the shelf to encourage purchase of oldest items first, or both. This process is time consuming and is subject to error. It is also very inefficient, because it requires all products with expiration dates to be checked, even if none of the units of a particular product are approaching their expiration dates. The accuracy and effectiveness of the expiration date management process is dependant upon the initiative and attention of the person or persons performing the work. The number of product units lost because they have passed their expiration dates can be substantial, and these losses can have a significant economic impact.
There is a need in the grocery industry and in other industries in which monitoring of expiration dates is necessary, for an efficient and accurate method of tracking product expiration dates to improve inventory management and assure that perishable packaged products can be sold before their expiration dates.